Gas tube boiler construction



July 6, 1954 E. DURHAM ET AL 2,682,861

' GAS TUBE BOILER CONSTRUCTION Filed Nov. 14, 1949 s Sheets-Sheet 1INVENTORS EDWIN DURHAM & GLEN J. SCHOESSOW ATTORNEY y 1954 E. DURHAM ETAL 7 2,682,861

GAS TUBE BOILER CONSTRUCTION Filed Nov. 14, 1949 3 Sheets-Sheet 2INVENTORS fDW/N DURHAM &'

Y GLEN J. SCHOESSUW O'l/MQ.

ATTORNEY y 1954 E. DURHAM ET AL GAS TUBE BOILER CONSTRUCTION 3Sheets-Sheet 3 Filed Nov. 14, 1949 ;\M-.. .ii

Wll!!!IIll!!!llrlvlllllllllllllIIIIIA/IllllllllliIIlllllllllllllllrlilvllllll FIG.5

INVEN TQRS 0w/- DURHAM db BY GLEN J. SCHOESSOW ATTORNEY ,ing vestibuleor the like.

Patented July 6, 1954 GAS TUBE BOILER CONSTRUCTION Edwin Durham,Westfield, N. J., and Glen J. Schoessow, Earberton, Ohio, assignors toThe Babcock & Wilcox Company, New York, N. Y., a corporation of NewJersey Application November 14, 1949, Serial No. 127,136

This invention relates to gas tube boilers of the waste heat recoverytype and, more particularly, to a novel joint between the gas tubesheet, the boiler shell, and the hot gas duct or vestibule.

.. Gas tube boilers of the waste heat type generally include exteriorshells, usually cylindrical,

having tube sheets'at either end supporting and positioning gas tubesdisposed within the shell. The shell and its tubes may be positioned inthe horizontal, vertical, or inclined position, de-

pending upon the conditions involved. One end vestibule, or stackarranged to receive the hot gases discharged from the tubes.

The interior of the shell, externally of the tubes therein, is arrangedto receive a liquid which is heated to a vapor by the hot gases flowingthrough the tubes. For this purpose, the shell interior is incommunication with a liquid and vapor drum, and the liquid circulatingpath includes downcomers connecting the drum to the shell interior atthe lower end and upcomers connecting the drum to the interior of theupper end of the shell.

.In the attachment of flanged ,tube sheets to the shell, in prior artconstructions where the shell has been extended beyond the planes of thetube sheet for welded attachment of the gas supply or exit ducts orvestibules, unsatisfactory stress conditions have been imposed on thejoint.

7 Claims. (61. 122512) perature, that of the saturated steam and waterwithin the shell. Consequently, the aforementioned temperature' strainsare. substantially completely eliminated.

While the tube sheets and the pressure confining portion of the shellare subject to the cooling effect of the liquid confined by the shelland the tube, sheets, the shell extensions projecting into thevestibules receive considerable heat from the high temperature gases,which later may be at temperaturesin excess of 1000 F. The,

temperature difierentials between the metal of 'failure of the joints.

To provide a moresuitable construction "adapted to the describedconditions, the present invention provides a novel tube sheet and anovel joining of the tube sheet, shell, and gas conduct- Specifically,the tube sheet is formed as an outwardly dished head or .dome having itsperipheral edge united to the endof the shell by a butt weld. The tubesheet, ,the boiler shell, and the joint therebetween are thusall exposedto substantially the same tem-.

,cular plate to prevent gas leakage.

weldedto the exteriors of the tube sheets and the shell, and areinterconnected by adjustable means, such as anchor bolts. A fiat annularplate is welded to the lugs on each tube sheet, and the correspondingvestibule or gas duct is welded to this plate enclosing a substantialportion of the adjacent tube sheet. A ring is welded to the tube sheetin such position that it has a close fit within the anular plate, and aflexible seal isprovided between the ring and the cir- For upright shellinstallations, to prevent steam entrapment beneath the upper tube sheet,compartment baffles are installed in front of the risers to require theliquid and vapor-to sweep over the upper part of the boiler. The anchorbolts, in conjunction with the annular plate welded to the vestibule,act as stress transmitting means connecting the vestibule to means onthe outer surface of the shell inwardly of the butt weld. Also, theannular plate and the lugs welded thereto provide means engaged betweenthe vestibule and the outer surface of the tube sheet and operative toresist outward movement of the tube sheet rela- In another embodiment ofthe invention, the

tive to the vestibule.

vestibules are formed with circumferentially spaced fingers fitting overand welded to the shell exterior inwardly of the joints between the tube.sheets and the shell. An inwardly dished annularring has its outerperiphery welded to the inner surface of each vestibule outwardly of thejunction of the fingers therewith. The inner periphery of this ring iswelded to the outer sur-" means engaged between the vestibule and thetube sheet and resisting movement of the latter outwardly relative tothe vestibule. This means, in conjunction with the fingers, is operativeto resist movement of the tube sheet outwardly from the shell. Thefingers act as stress transmitting means connecting the vestibule to theshell inwardly of the butt weld. In this embodiment, however, theinwardly dished ring also forms a major part of the gas seal between thevestibule and the tube sheet.

In both embodiments, ferrules are preferably placed in the tube ends toeliminate erosion of the tube inner surfaces at the entrance .zone ofhigh gas turbulence. With refractory material placed therearound, theseferrules limit heat input-t the tube sheet.

With the foregoing in mind, it is an object of the present invention toprovide a novel gas tube boiler construction.

Another object is to provide, in a gas tube boiler, a novel joiningarrangement between the tube sheets, gas vestibules or ducts and theboiler shell.

Afurther object is to provide such a joint so located that the tubesheets, the shell, and'the joint therebetween are all kept atsubstantially the same temperature.

Yet another objectis to provide such a joint including means reinforcingthe same against pressure stresses.

These and other objects, advantages, and novel features of theinventionwill be apparent from the following description and theaccompanying drawings.

In the drawings:

Fig. 1 is a front elevation view partly in section, of a gas tube boilerembodying the invention;

Fig. 2 is a side elevation view of the boiler;

Fig. 3 is an enlarged partial longitudinal sectional view of one end ofthe shell and tube sheet enclosure, illustrating the novel joining ofthe shell, the tube sheet, and the hot gas vestibule or duct;

Fig. 4 is a partial side elevation view of the shell and vestibule ofFig. 3; and

Fig. 5 is a view, similar to Fig. 1, illustrating another embodiment ofthe invention.

Referring first to Figs. 1 and 2 of the drawings,

agas tube boiler l0, such-as of the waste heat type, is illustrated ascomprising an upright, somewhat inclined, pressure confining enclosureincluding a shell l5'and'tube sheets 30, 30',

and a liquid and vapor-drum '25. Hot gases are 'manhole l3 and beclosed'by-a cap 'orcover l4.

Exit duct or vestibule 40 is-hopper shaped, tapering to a dischargeopening 16.

Shell i5 is suitably supported on brackets, such as H, and drum 25 onbrackets 18. Drum 25 has afeed water inlet 2|, steam outlet 22, vent 23,safety valve connections 24, and a gauge 26. Liquid, such as Watenentersthe bottom portion of the pressure confining enclosure from drum 25through downcomers 2-1, and :vapor or steam .:a drain I for drum 25,both terminating in a T- connection 8.

Referring to Figs. 3 and 4, the tube sheet 30 comprises an outwardlydished or dome shaped member in which the ends of tubes are secured byextending through holes 3| in the tube sheet and being welded to thelatter as at 32.

The inwardly extending periphery 33 of sheet is secured to the endperiphery 34 of shell I5 by a butt weld, as indicated at 45. The joint45, as

well as the joined ends of shell 15 and sheet 30,

are thus subjected to the temperature of the liquid and vapor in theshell, which is the same temperature to which the main portion of thetube is exposed.

The inner end of vestibule 35 has circumferentially spaced fingers 36with circumferentially extended outer ends 31, the fingers 3B embracingand engaging shell l5 inwardly of weld 45. An inwardly dished annularplate encloses the space between tube sheet 30 and vestibule 35. Tosecure plate 58 to sheet 30 and vestibule 35. an annular weld deposits!having a horizontally plane upper surface is formed on the outer surfaceof sheet 30. A pair of weld deposits '53, 54 are then formed on theinner and outer peripheries of the inner surface, respectively, of plate50, the outer surfaces of the weld deposits being flush with suchperiphery. Plate 50 is then placed with its inner periphery resting onweld deposit 5|, and a welded joint is formed to unite deosits 5| and 53and the inner periphery of plate 50. vestibule 35 is then slipped overthe assembly and a weld 52 is formed to unite vestibule 35 to deposit 54and the outer periphery of plate '50. Finally, fillet welds 56 areformed between extensions '31 and the outer surface of shell 15.

The plate 50, with its welded joints to the vestibule and the tubesheet, forms a gas tight seal between these elements. The plate 5!! actsas a compressive stress transmitting means between the vestibule and thetube sheet and, in conjunction with fingers 36, acts to resist outwardmovement of the tube sheet from the shell. Ferrules 63 preferably areinserted in the ends of tubes 20 and refractory material packed aroundthe ferrules within the vestibule and on the .outer surface of tubesheet 3i] in the same manner as will be described in connection withFig. 5. The openings 51 formed between the circumferentially spacedfingers 36 allow access for inspection of the inwardly extendedperiphery .33 and welded joint 45.

'When the shell [5 is arranged to extend upwardly as illustrated inFigs. 1 and 2, there is some tendency for vapor pockets to form undertube sheet 30. For the purpose, baffles 4| are arranged inwardly of theopen ends of therisers or upcomers, such as 28. These baffles cause theliquid and vapor to sweep over the inner surface of the tube sheetbefore entering the riser tubes.

Fig. 5 illustrates a modified form of joining of the tube sheet to theliquid and vapor shell. In this construction, tube sheet 30 is the sameas in Figs. 3 and 4, being an outwardly dished dome shaped member havingits inner periphery 33 secured to the end periphery 34 of shell'l5 by a'butt weld 45'. Tubes 20 extendthrough holes 2| outwardly-relative tothe vestibule.

f in sheet and are secured to the sheet by welds 32.

U-shaped brackets 42 are mounted on the curved outer surface of sheet 30and have outwardly opening slots 43 in their bases 44. Other U-shapedbrackets 46 are secured to the external surface of shell l5 inwardly ofweld joint 45'. "Bolts 4'! extending through apertures in brackets 46and through slots 43 secure the vestibule to the shell.

Brackets 42 also'serve to support the gas duct or vestibule 35. For thispurpose, annular plate 6| is mounted on brackets 42 and welded theretoas at 62. The vestibule is supported on plate or ring 6| and a welded.joint 63 forms a gas tight seal between the vestibule and plate 6|,securing these two elements together. To

complete the gas tight assembly of vestibule 35 to tube sheet 30, a ring651s secured to the tube sheet 30 by a weld 66, ring 65 being disposedwithin and'closely adjacent the rear periphery of plate 6|. A flexiblesealing ring 61closes the joint between rings 6| and 65. The ring 5|welded to lugs 42 acts with the latter as means engaged between thevestibule 35 and the tube sheet 3n operative to resist movement of thetube sheet The lugs 42, ring 6|, bolts 47, and lugs 46 form stresstransmitting means connecting the vestibule to the shell inwardly of thebutt weld.

To reduce oreliminate the securing action of gases on the end portionsof tubes 20, ferrules tributing to the elimination of the abovetemperature differential strains. Bafile 4| may have a drain opening 63in its lower wall 69.

The lower tube sheet 30' and the gas exit vesti-.

bule or duct are secured to shell I5 in the same manneras described forupper tube sheet 38 and gas entrance vestibule or duct 35. In all cases,the described connections provide for limited relative movement of thejoined elements to avoid destructive stresses.

While specific embodiments have been shown and described in detail toillustrate the application of the invention principles, it will beunderstood that the invention may be otherwise embodied withoutdeparting from such principles.

We claim:

1. In a gas tube boiler construction, a boiler shell arranged to formpart of a liquid and vapor containing enclosure for the hot gasconducting tubes of the boiler; an outwardly dished tube sheet includedin the enclosure and formed to have the gas tubes secured therein, saidtube sheet having an inwardly extending peripheral rim; a continuousbutt weld joint uniting the peripheral rim of said tube sheet to an endof said shell, said joint being located in heat transfer relation to theliquid and vapor space provided by said enclosure; a gas conductingvestibule extending outwardly of said tube sheet in communication withthe gas tubes; stress transmitting means connecting said vestibule tothe outer surface of said shell inwardly of said butt weld joint; andmeans engaged between said vestibule and the outer surface of said tubesheet and operative to resist outward movement of said tube sheetrelative to said vestibule, said lastnamed means comprising alsogas-tight sealing means between the tube sheet and the vestibule.

2. In a gas tube boiler construction an upwardly extending boiler shellarranged to form part of a liquid and vapor containing enclosure for thehot gas conducting tubes of the boiler;

an integral outwardly dished tube sheet included in the enclosure andformed to have the gas tubes secured therein, said tube sheet having aninwardly extending peripheral rim congruent with an' end edge of theshell; a continuous butt weld. 'joint uniting the peripheral rim of saidtube sheet to theupper end edge of said shell; risers com municatingwith the upper end of said shell downwardly of said butt weld joint; anda baflle within the interior of said shell in front of the openings intosaid; risers to force the liquid and vapor to sweep over the innersurface of said tube sheet and said joint to enter said risers toprevent formation of a vapor pocket under said tube sheet.

3. In a gas tube boiler construction, a boiler 'shell arranged to formpart of a liquid and vapor containing enclosure for the hot gasconducting tubes of the boiler; an outwardly dished tube sheet includedin theenclosure and formed to have the gas tubes secured therein, saidtube sheethaving an inwardly extending peripheral rim; a continuous buttweld joint uniting the peripheral rim of said tube sheet to an end ofsaid shell, said joint being located in heat transfer relation to theliquid and vapor space provided by said enclosure; risers communicatingwith the upper end of said shell downwardly of said butt weld joint; abaflie within the interior of said shell in frontof the openings intosaid -risers to force the liquid and vapor to sweep over the innersurface of said tube sheet and said joint to enter said risers toprevent formation of a vapor pocket under said tube sheet; first anchorlugs secured to the exterior of said tube sheet; second anchor lugssecured to the exterior of said shell; means interconnecting said firstand second anchor lugs; an annular plate mounted on said first anchorlugs; a gas conducting vestibule extending outwardly of said tube "sheetin communication with the gas tubes and welded to said plate adjacentthe outer edge thereof a ring welded to said tube sheet adjacent theinner periphery of said annular plate; and means forming a gas-tightseal between said ring and said plate.

4. In a gas tube boiler construction, a boiler shell arranged to formpart of a liquid and vapor containing enclosure for the hot gasconducting tubes of the boiler; an outwardly dished tube sheet includedin the enclosure and formed to have the gas tubes secured therein, saidtube sheet having an inwardly extending peripheral rim; a continuousbutt weld joint uniting the peripheral rim of said tube sheet to an endof said shell, said joint being located in heat transfer relation to theliquid and vapor space provided by said enclosure; a gas conductingvestibule extending outwardly beyond said tube sheet in communicationwith the gas tubes and having 5 its inner end secured to said shell; andan incontaining enclosure for the hot gas conducting tubes of theboiler; an outwardly dished tube sheet included in the enclosure andformed to have the gas tubes secured therein, said tube sheet having aninwardly extending peripheral rim; a continuous butt weld joint unitingthe peripheral rim of said tube sheet to an end of said shell, saidjoint being located in heat transfer relation to the li uid and vaporspace provided by said enclosure; a gas conducting vestibule extendingoutwardly beyond said tube sheet in communication with the gas tubes andembracing said shell inwardly of said joint; a welded joint securing theinner end of said vestibule to the outer surface of said shell; and aninwardly dished annular plate having its outer peripheral margin weldedto the inner surface of said vestibule and its inner peripheral marginWelded to the outer surface of said tube sheet to form a gas-tight sealbetween said tube sheet and said vestibule.

'6. In a gas tube boiler construction, a boiler shell arranged to formpart of a liquid and vapor containing enclosure for the hot gasconducting tubes of the boiler; an outwardly dished tube sheet includedin the enclosure andformed to have the gas tubes secured therein, saidtube sheet having an inwardly extending peripheral rim; a continuousbutt weld joint uniting the peripheral rim of said tube sheet to an endof said shell, said joint being located in heat transfer relation to theliquid and vapor space provided by said enclosure; a gas conductingvestibule extending outwardly beyond said tube sheet in communicationwith the gas tubes, said vestibule having circumferentially spacedfingers embracing said shell inwardly of said joint; Welded jointssecuring the inner ends of said fingers to the outer surface of saidshell; and an inwardly dished annular plate having its outer peripheralmargin welded to the inner surface of said vestibule and its innerperipheral margin welded to the outer surface of said tube sheet to forma gas-tight seal between said tube sheet and said vestibule; the spacesbetween said fingers forming access handholes.

7. In a gas tube boiler construction, a boiler shell arranged to formpart of a liquid and vapor containing enclosure for the hot gasconducting tubes of the boiler; an outwardly dished tube sheet includedin the enclosure and formed to have the gas tubes secured therein, saidtube sheet having an inwardly extending peripheral rim; a continuousbutt weld joint uniting the peripheral rim of said tube sheet to an endof said shell, said joint being located in heat transfer relation to theliquid and vapor space provided by said enclosure; a gas conductingvestibule extending outwardly beyond said tube sheet in communicationwith the gas tubes and embracing said shell inwardly of said joint; awelded joint securing the inner end of said vestibule to the outersurface of said shell; an inwardly dished annular plate disposed insidesaid vestibule and having built up weld deposits on its concave surfacearound each periphery; an annular built up weld deposit on the outersurface of said tube sheet; and a pair of Welds respectively uniting onebuilt up Weld deposit on said plate to said annular built up welddeposit on said tube sheet, and the other plate weld deposit to theinner surface of said vestibule to form a gas-tight seal between saidtube sheet and said vestibule.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 204,461 Trump June 4, 1878 547,045 Sturtevant Oct. 1, 1895537,683 Ernst Aug. 3, 1897 601,488 Thompson Mar. 29, 1898 750,916Villiers Feb. 2, 1904 1,188,968 Meier June 27, 1916 1,230,990 Bone et a1June 26, 1917 1,290,091 Cole Jan. 7, 1919 1,300,873 Quinn Apr. 15, 19191,611,040 Jahn et al Dec. 14, 1926 1,680,380 Jahn et al Aug. 14, 19281,878,172 Noble Se t. 20, 1932 1,894,957 Lucke et a1 Jan. 24, 19331,924,209 Kilgour Aug. 29, 1933 2,035,605 Jackson Mar. 31, 19362,076,585 Merker Apr. 13, 1937 2,138,321 Bratasianu Nov. 29, 19382,344,269 'Saco Mar. 14, 1944 2,464,701 Lyke Mar. 15, 1949 FOREIGNPATENTS Number Country Date 15,179 Great Britain July 26, 1901 19,803Great Britain Sept. 5, 1906 98,648 Switzerland Apr. 2, 1923 299,085Great Britain Oct. 22, 1928

